Bushing

ABSTRACT

A system for passing a cable, a conduit, a pipe or the like sealingly through an opening in a wall, comprising a sealing device made of an elastic material, such as rubber, which includes at least one lead-through channel having a smooth inner wall, wherein the sealing device is externally provided with axially spaced-apart, circular, at least substantially inflexible, compressible ribs lying in (imaginary) radial planes, whose outside diameter is larger than the inside diameter of the opening, and wherein the system furthermore includes at least one grommet to be fitted round the cable, the conduit, the pipe or the like that is to be passed through, which grommet can be fitted sealingly in said lead-through channel, which grommet, which has a smooth outer side, includes a bore whose wall is provided with axially spaced-apart, circular, at least substantially inflexible, compressible ribs lying in (imaginary) radial planes, whose inside diameter is at least substantially identical to the outside diameter of the cable, the conduit, the pipe or the like that is to be passed through.

[0001] The invention relates to a system for passing a cable, a conduit,a pipe or the like sealingly through an opening in a wall, comprising asealing device made of an elastic material, such as rubber, whichincludes at least one lead-through channel having a smooth inner wall,wherein the sealing device is externally provided with axiallyspaced-apart, circular, at least substantially inflexible, compressibleribs lying in (imaginary) radial planes, whose-outside diameter islarger than the inside diameter of the opening, and wherein the systemfurthermore includes at least one grommet to be fitted round the cable,the conduit, the pipe or the like that is to be passed through, whichgrommet can be fitted sealingly in said lead-through channel. It isnoted in this connection that the term “wall” is understood to include awall, a partition, a ship's deck, in short, any partition for sealedpassage therethrough of a cable, a conduit, a pipe or the like.

[0002] Such a system is known from European patent no. 0 278 544 in thename of the present applicant. The known system provides a cylindricalsealing device, which comprises a number of eccentrically disposedcylindrical lead-through channels, as well as an identical number ofgrommets, which must each be inserted into a corresponding lead-throughchannel. Each grommet consists of several segments having a smooth innerside and being provided with so-called ridges on the outer side, whichare to be arranged around single cables passing through. Not only willthe segments sealingly press on the electrical cables passing throughwhen a grommet is being forced into a lead-through channel, but also theridges and the smooth inner wall of the lead-through channel will besqueezed together sealingly.

[0003] One drawback of the system as known from the aforesaid Europeanpatent is that leakage sometimes develops in practice, in particularbetween the smooth inner side of the grommet and the more or less smoothouter surface of the electrical cables passing through, since thediameter of the cables passing through may vary owing to productiontolerances; said tolerance differences cannot easily be compensated bythe material of the grommet and/or the cables.

[0004] The object of the invention is to provide a sealing system whichprovides an improved sealing result, wherein no leakage will occur.

[0005] In order to accomplish that objective, a system of the kindreferred to in the introduction is characterized in that said grommet,which has a smooth outer side, includes a bore whose wall is providedwith axially spaced-apart, circular, at least substantially inflexible,compressible ribs lying in (imaginary) radial planes, whose insidediameter is at least substantially identical to the outside diameter ofthe cable, the conduit, the pipe or the like that is to be passedthrough. Since the inside diameter of the (inner) ribs Is preferablylarger than the outside diameter of the cable, the conduit, the pipe orthe like passing through, said ribs will be slightly compressed duringuse, as a result of which a pressure-resistant seal is formed on theouter surface of the cable, the conduit, the pipe or the like passedthrough, thus preventing leakage along said outer surface—also in thecase of tolerances in the cable diameter. At the same time, the smoothinner wall of the bushing and the smooth outer surface of the grommetsqueeze against each other sealingly.

[0006] In one preferred embodiment of a system according to theinvention, the lead-through channel is of at least substantiallyrectangular or square cross-section. This makes it possible inparticular to use a grommet which comprises a parallelopiped blockformed of two identical halves, which halves can be fitted round thecable, the conduit, the pipe or the like to be passed through.

[0007] In another preferred embodiment of a system according to theinvention, the smooth inner wall of the lead-through channel abutsagainst the smooth outer wall of the grommet in the position of use.Preferably, at least two grommets are used, which can be fittedsealingly in the lead-through channel. One of said grommets may be ablind grommet, if part of the lead-through channel is not being used andneeds to be closed, therefore.

[0008] The invention furthermore relates to a bushing and/or a grommetapparently suitable for use in a system according to the invention.

[0009] The invention will now be explained in more detail with referenceto a FIGURE that is shown in a drawing, which schematically shows apreferred variant of a system according to the invention in perspectiveview. The FIGURE shows a cylindrical sealing device 1 having a smooth,rectangular lead-through channel 2. This sealing device is externallyprovided with serrated, in cross-sectional view, outer ribs 3 lying in(imaginary) radial planes, which are inflexible, practically speaking,but which are substantially compressible. In order to facilitate theinsertion of the sealing device 1 into a wall opening, vaseline oranother lubricant may be applied to the outer ribs 3 before saidinsertion takes place. Insertion takes place over a distance defined bya flange 4 abutting against the edge of a wall opening. In order toprevent the sealing device 1 from being forced out of a wall opening tooeasily, the outer ribs 3 are serrated, seen in cross-sectional view. Inorder to obtain a pressure-resistant, gastight, watertight and fireproofseal, the outside diameter of the outer ribs 3 must be larger than theinside diameter of a wall opening to be sealed. In practice, the bottomside and the flange side of the sealing device 1 have a pressureresistance of, respectively, 1 bar and 2 bar. Once the sealing device 1has been pressed into a wall opening, the electricity cables 5 can bepassed through the lead-through channel 2. Following that, two identicalblock halves 6 of a block-shaped cable grommet 7 must be fitted round anelectric cable 5 and subsequently be inserted into the lead-throughchannel 2, which can be done by means of a mallet. The inner ribs 8 oftrapezoidal cross-section that are present on the inner side of thecable grommet 7 have an inside diameter which is larger than the outsidediameter of the electric cable 5 in question that is to be passedthrough. When the cable grommets 7 are inserted into the lead-throughchannel 2, this will not only cause the block halves 6 to presssealingly on the respective electric cable 5 that is to be passedthrough, but the smooth outer sides of the grommets 7 (block halves 6) 8and the inner wall of a lead-through channel 2 will also be squeezedtogether sealingly. An unused part of the lead-through channel 2 of thesealing device 1 may be closed by, for example, a blind grommet 9comprising two identical block halves. In the position of use, a sealingpressure will be obtained between the outer sides of adjacent,block-shaped grommets 7 and between the walls of their bores and theouter sides of cables 5 present therein, and also between the outersides of the block-shaped grommets 7 and the inner wall of thelead-through channel 2, such that leakage will not occur in practice. Onthe rear side of the lead-through channel 2, each half of the sealingdevice 1 is provided with a bumper edge 10 to prevent the block halves 6being inserted too far.

[0010] The possibility to fit several block-shaped grommets 7 havingmutually different bore diameters in the rectangular lead-throughchannel 2 provides much greater flexibility in passing through cables 5having mutually different diameters than is possible with the systemaccording to the aforesaid European patent publication no. 0 278 544;after all, said prior art bushing comprises a fixed pattern of identicallead-through channels. In addition, said identical lead-through channelsneed to be spaced a minimum distance apart in order to impart somerigidity to the known bushing, with the inherent drawback that the knownbushing takes up a relatively great deal of space. Finally, because theaforesaid prior art sealing device is made in one piece, it cannot beused with cables that are in place already; with the sealing device 1according to the invention, on the other hand, this is possible, sinceit comprises two identical halves.

[0011] The invention is not restricted to the preferred variant asshown, but also other embodiments can be realised without departing fromthe scope of the invention as defined in the appended claims.

1. A system for passing a cable, a conduit, a pipe or the like sealinglythrough an opening in a wall, comprising a sealing device made of anelastic material, such as rubber, which includes at least onelead-through channel having a smooth inner wall, wherein the sealingdevice is externally provided with axially spaced-apart, circular, atleast substantially inflexible, compressible ribs lying in (imaginary)radial planes, whose outside diameter is larger than the inside diameterof the opening, and wherein the system furthermore includes at least onegrommet to be fitted round the cable, the conduit, the pipe or the likethat is to be passed through, which grommet can be fitted sealingly insaid lead-through channel, characterized in that said grommet, which hasa smooth outer side, includes a bore whose wall is provided with axiallyspaced-apart, circular, at least substantially inflexible, compressibleribs lying in (imaginary) radial planes, whose inside diameter is atleast substantially identical to the outside diameter of the cable, theconduit, the pipe or the like that is to be passed through.
 2. A systemaccording to claim 1, wherein said lead-through channels is of at leastsubstantially rectangular or square cross-section.
 3. A system accordingto claim 1 or 2, wherein said grommet comprises a parallelopiped blockformed of two identical halves, which halves can be fitted round thecable, the conduit, the pipe or the like to be passed through.
 4. Asystem according to claim 1, 2 or 3, wherein the smooth inner wall ofthe lead-through channel abuts against the smooth outer wall of thegrommet in the position of use.
 5. A system according to any one of thepreceding claims 1-4, wherein at least two grommets are used, which canbe fitted sealingly in the lead-through channel.
 6. A system accordingto claim 5, wherein one of said grommets is a blind grommet.
 7. Agrommet apparently suitable for use in a system according to any one ofthe preceding claims 1-6.
 8. A bushing apparently suitable for use in asystem according to any one of the preceding claims 1-6.